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2-9. RESET CIRCUIT
j
KX-t- i200
The output from pin 3 of the Reset IC (IC409) resets the CPU (IC401), the gate array (IC404), the modem (IC405), the gate
array on the operating board (IC301), the Port IC (IC1) on the analog board through the IC410.
(1) During to momentary power interruption, a positive reset pulse of 175 msec or more is generated and the system is reset
completely.
This is done to prevent partial resetting and system runaway during power fluctuation.
Timing Chart
+5
" 4.3
JJ
4.2 _Fv_,
4.3
J}
!about 175 ms j_
bout 175 ms Jl
i
i
i
i
i
i
(2) When pin 3 of the IC409 becomes low level, it will prohibit the RAM (IC403) from changing data.
The RAM (IC403) go into the backup mode, when they are backed up by the lithium battery.
+5V
C701
-
7
IC409
Circuit Diagram
RAMCS
J20
i_
24
F'_
IC417
R703
WDERR
]
I 38 1
RESET (TO ANALOG BOARD)
36
I
19
I
37
I
RAM (IC403)
IC411
RESET (TO OPERATION
BOARD)
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